A scaffold assembly and method of manufacture

ABSTRACT

The present invention provides a scaffold assembly, in particular a combination of a conventional tubular scaffold tube or pole and a rosette type coupling which enables the connection of additional scaffold components to the scaffold assembly, the coupling and tubular element being fixed relative to one another by means of at least one abutment which is cold formed in the tubular element such as to fix the coupling in position relative thereto.

FIELD OF THE INVENTION

This invention relates to a scaffold assembly and a method of manufacturing same, in particular a scaffold assembly which includes a tubular element such as a conventional scaffold upright, and one or more brackets or couplings, for example a conventional scaffold rosette, uniquely secured to the upright without any requirement for welding or additional fixings.

BACKGROUND OF THE INVENTION

Scaffold systems and assemblies are used in a large number of applications, most notably to allow individuals such as construction workers or the like to gain access to difficult to reach areas, often at elevated heights, in order to carry out construction work, repairs, inspections, etc.

While the majority of scaffold assemblies consist exclusively of interconnected uprights and cross members, there is often a requirement for the connection of one or more scaffold components positioned at an angle to the vertical uprights or horizontal cross members. In such arrangements it is conventional to utilise an upright or cross member onto which has been welded or otherwise secured a coupling such as a “rosette” which enables the angled connection of one or more scaffold components.

However, the welding of a coupling to aluminium scaffold can give rise to a number of problems, in particular a weakening of the aluminium surrounding the weld, which is effectively heat treated as a result of being subjected to the heat of the welding process. The can give rise to a localised failure of the scaffold component, and given that this component may be a structural part of a much larger scaffold assembly, can be an extremely dangerous issue.

In addition, the process of welding aluminium scaffold is a costly and time consuming process, and it is therefore an object of the present intention to provide a scaffold assembly and a method of manufacture which does not require welding, in which the securing of two scaffold parts to one another can be performed as a cold operation.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a scaffold assembly comprising a hollow tubular element; and a coupling circumscribing the tubular element; characterised in that the coupling is secured in position by at least one abutment formed as a localised outward deformation of the tubular element.

Preferably, the scaffold assembly comprises a pair of axially spaced abutments between which the coupling is captured.

Preferably, the coupling comprises a recess opening onto an interface between the coupling and the tubular element, and at least one abutment formed as a localised outward deformation into the recess.

Preferably, the at least one abutment comprises an annular deformation of the tubular element.

Preferably, the coupling comprises a rosette. Preferably, the tubular element is formed from aluminium.

Preferably, the at least one abutment is formed as a deformation extending from an inner wall to an outer wall of the tubular element.

Preferably, the axial spacing between the first and second abutments is substantially equal to the thickness of the coupling.

Preferably, the tubular element comprises a scaffold upright.

Preferably, the coupling is formed integrally with a scaffold component.

According to a second aspect of the present invention there is provided a method of manufacturing a scaffold assembly comprising a hollow tubular element and a coupling circumscribing the tubular element, the method comprising locally outwardly deforming the tubular element to form an abutment positioned to retain the coupling in position.

Preferably, the method comprises the step of forming a pair of abutments axially spaced along the tubular element, between which the coupling is captured.

Preferably, the method comprises the steps of providing a recess in the coupling opening onto an interface between the coupling and the tubular element; and forming at least one abutment as an outward deformation into the recess.

Preferably, the method comprises cold forming the or each abutment.

Preferably, the method comprises forming the or each abutment through deformation of the tubular element from an inner wall of the tubular element. Preferably, the method comprises the step of inserting a forming tool into a hollow interior of the tubular element; and expanding at least a portion of the forming tool in order to form the abutments.

Preferably, the method comprises utilising hydraulic pressure in order to effect expansion of the forming tool.

Preferably, the method comprises radially outwardly expanding an annular array of discrete forming elements comprised in the forming tool.

Preferably, the method comprises forcing a conical wedge against the array of forming elements in order to effect the radially outward expansion of the annular array.

Preferably, the method comprises securing the tubular element and coupling in a forming jig prior to undertaking deformation of the tubular element.

As used herein, the term “axially” is intended to refer to a longitudinal axis of the tubular element, for example an elongate hollow scaffold pole or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of a scaffold assembly according to an embodiment of the present invention, including a rosette type coupling and a tubular element secured together;

FIG. 2 illustrates a side elevation of the scaffold assembly as illustrated in FIG. 1;

FIG. 3 illustrates the tubular element forming part of the scaffold assembly shown in FIGS. 1 and 2 in isolation from the coupling;

FIG. 4 illustrates a perspective view of a forming tool used in the method according to the present invention for securing the coupling to the tubular element;

FIG. 5 illustrates a perspective view from one end of the scaffold assembly illustrated in FIGS. 1 and 2, and having the forming tool illustrated in FIG. 4 inserted into the tubular element as illustrated in isolation in FIG. 3;

FIG. 6 illustrates a perspective view of the scaffold assembly shown in FIGS. 1 and 5 mounted in a forming jig; and

FIG. 7 illustrates a sectioned view of the scaffold assembly according to the invention and having an additional abutment for securing the coupling to the tubular element.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the accompanying drawings there is illustrated a scaffold assembly, generally indicated as 10, for use with general scaffold constructions in order to facilitate the connection of one or more scaffold components (not shown) to a scaffold upright or other scaffold element, which scaffold component (not shown) can then extend at any desired angular orientation relative to the scaffold upright. Such an arrangement is well known and utilised in conventional scaffold constructions. However, the manner and method by which the scaffold assembly 10 of the present invention is constructed is novel.

The scaffold assembly 10 comprises a hollow tubular element 12, preferably formed from aluminium but may be formed from any other suitable material, for example stainless steel or the like, and a coupling in the form of a rosette 14 which is secured about the exterior of the tubular element 12 as will be described in detail hereinafter. Although the tubular element 12 is illustrated as a relatively short length, it will be appreciated that in use the tubular element 12 will be of any suitable length to function as a scaffold upright or alternative scaffold element. In addition, it will be appreciated that the rosette 14 could be of any other suitable form, and indeed could be replaced with any other coupling permitting the connection of one or more scaffold elements (not shown) to the tubular element 12. The coupling 14 could also be formed integrally with the one or more scaffold components (not shown) to be connected to the tubular element 12.

Referring in particular to FIGS. 1 and 2 it can be seen that the rosette 14 is secured in position on the exterior of the tubular element 12 by means of a first abutment 16 and an axially-spaced second abutment 18 between which a channel 20 (only visible in FIG. 3) is formed and within which the rosette 14 is captured. The rosette 14 is thus effectively clamped between the first and second abutments 16, 18 in order to prevent axial displacement along the tubular element 12, in addition to preferably preventing any rotation of the rosette 14 on the tubular element 12. The tubular element 12, including the first and second abutments 16, 18 is shown in isolation from the rosette 14 in FIG. 3. The use of the pair of abutments 16, 18 to clamp the rosette 14 in position avoids the requirement for welding between the tubular element 12 and the rosette 14, or the use of any additional fixing hardware or the like.

In the preferred embodiment of the invention the scaffold assembly 10 is cold formed by deforming portions of the tubular element 12 in order to form the first and second abutments 16, 18. In a particularly preferred embodiment, and referring to FIG. 4, an expanding tool 22 is utilised to form the first and second abutments 16, 18 in the tubular element 12. The expanding tool 22 comprises an annular array of discrete forming elements 24 which may be expanded radially outwardly from the positions shown in FIG. 4. As an annular array the forming elements define a pair of raised ridges 25 which circumscribe the tool 22.

The radial displacement of the forming elements 24 may be effected by any number of suitable methods, and for example may be achieved by means of an expanding wedge type arrangement whereby a plunger 26 having a substantially conical nose (not shown) is driven into the centre of the annular array of forming elements 24, in order to splay or expand the individual forming elements 24 radially outward. The plunger 26 may be driven by any suitable means, whether mechanical, hydraulic, pneumatic or otherwise. Once the pressure is removed from the plunger 26 it will revert to the position illustrated in FIG. 4, thereby allowing the individual forming elements 24 to be retracted radially inwardly to permit removal of the tool 22 from within the tubular element 12.

Thus in use the forming tool 22, in the retracted state as illustrated in FIG. 4, is inserted into a lumen 28 defining the hollow interior of the tubular element 12. This arrangement is illustrated in FIG. 5, with the plunger 26 of the forming tool 22 omitted in order to illustrate the interior of the annular array of forming elements 24. Prior to insertion of the tool 22 the scaffold assembly 10 may preferably be seated within a forming jig 30. The jig 30 is adapted to hold the tubular element 12 and the rosette 14 immobilised on the exterior of the tubular element 12. At this point the forming tool 22 is located at the correct axial position within the lumen 28, such that the tow rings of ridges 25 are located at the positions at which the first and second abutments 16,18 are to be formed. Pressure is then applied to the plunger 26, preferably hydraulic pressure, thus driving the plunger 26 against the interior of the forming elements 24 in order to effect the radially outward displacement of the forming elements 24.

This outward expansion forces the two annular ridges 25 against an interior wall 32 of the tubular element 12. Further pressure applied to the plunger 26 will then begin to effect localised deformation of the tubular element 12, forcing the aluminium or other material of the tubular element 12 outwardly to define the first and second abutments 16, 18. Once the abutments 16,18 have been fully formed, the pressure can be released from the plunger 26 allowing the individual forming elements 24 to be retracted, for example by means of a spring or other suitable biasing means. The forming tool 22 can then be removed from within the lumen 28 of the tubular element 12, and the scaffold assembly 10 then removed from the forming jig 30. At this point the rosette or other coupling 14 is securely mounted to the tubular element 12, and the scaffold assembly 10 is ready for use.

Referring now to FIG. 7, the scaffold assembly 10 is illustrated in section, and only one half is shown, the assembly 10 being symmetrical about a longitudinal axis L of the tubular element 12. in order to further secure the coupling 14 in position, and to increase the load carrying capacity, a further abutment 32 may be formed in the tubular element 12, again preferably an annularly extending abutment 32, at the location where the coupling 14 overlies the tubular element 12. A recess 34, again preferably extending annularly, is provided in the coupling 14 and opening onto the interface between the tubular element 12 and the coupling 14. In this way the abutment 32 will be deformed outwardly during formation in order to at least partially fill the recess 34. It is preferable that the abutment 32 substantially fills the recess 34, more preferably with a slight interference fit, in order to provide maximum load bearing capacity. The arrangement shown in FIG. 7 intentionally exaggerates the size of the recess 34 relative to the abutment 32 for illustrative purposes.

The abutment 32 may be formed in the same was as described above with reference to the abutments 16, 18. The recess 34 is machined or otherwise formed in the coupling 14 prior to assembling the tubular element 12 and coupling 14 together. It is also envisaged that, depending on the load carrying capacity of the assembly 10, the pair of abutments 16, 18 could be omitted and the abutment 32 solely used to secure the coupling 14 in position.

It will be appreciated that the above mentioned method may be fully automated, and thus a cold forming process can be performed at significantly increased speed relative to existing methods of securement such as welding or the like. In addition, the absence of heat then avoids the shortcomings of welding, in particular in connection with the welding of aluminium, which can lead to material distortion, unintended heat treatment and thus weakening of the surrounding aluminium, porosity of the weld, poor finish to the weld, etc.

Thus the assembly 10 of the present invention, and the method of manufacturing same, provide an alternative means of securing a coupling or the like to a tubular scaffold element, which is fully automatable, cost effective, and eliminates the problems associated with alternative means of joining such components.

The invention is not limited to the embodiment described herein but can be amended or modified without departing from the scope of the present invention. 

1. A scaffold assembly comprising a hollow tubular element; and a coupling circumscribing the tubular element; characterised in that the coupling is secured in position by at least one abutment formed as a localised outward deformation of the tubular element.
 2. A scaffold assembly according to claim 1 comprising a pair of axially spaced abutments between which the coupling is captured.
 3. A scaffold assembly according to claim 1 in which the coupling comprises a recess opening onto an interface between the coupling and the tubular element, and at least one abutment formed as a localised outward deformation into the recess.
 4. A scaffold assembly according to claim 1 in which the at least one abutment comprises an annular deformation of the tubular element.
 5. A scaffold assembly according to claim 1 in which the coupling comprises a rosette.
 6. A scaffold assembly according to claim 1 in which the tubular element is formed from aluminium.
 7. A scaffold assembly according to claim 1 in which the at least one abutment is formed as a deformation extending from an inner wall to an outer wall of the tubular element.
 8. A scaffold assembly according to claim 2 in which the axial spacing between the pair of abutments is substantially equal to the thickness of the coupling.
 9. A scaffold assembly according to claim 1 in which the tubular element comprises a scaffold upright,
 10. A scaffold assembly according to claim 1 in which the coupling is formed integrally with a scaffold component.
 11. A method of manufacturing a scaffold assembly comprising a hollow tubular element and a coupling circumscribing the tubular element, the method comprising locally outwardly deforming the tubular element to form an abutment positioned to retain the coupling in position.
 12. A method according to claim 11 comprising the step of forming a pair of abutments axially spaced along the tubular element and between which the coupling is captured.
 13. A method according to claim 11 comprising the steps of providing a recess in the coupling opening onto an interface between the coupling and the tubular element; and forming at least one abutment as an outward deformation into the recess.
 14. A method according to claim 11 comprising cold forming the or each abutment.
 15. A method according to any of claim 11 comprising forming the or each abutment through deformation of the tubular element from an inner wall of the tubular element.
 16. A method according to claim 11 comprising the step of inserting a forming tool into a hollow interior of the tubular element; and expanding at least a portion of the forming tool in order to form at least one abutment.
 17. A method according to claim 14 comprising utilising hydraulic pressure in order to effect expansion of the forming tool.
 18. A method according to claim 16 comprising radially outwardly expanding an annular array of discrete forming elements comprised in the forming tool.
 19. A method according to claim 16, comprising forcing a conical wedge against the array of forming elements in order to effect the radially outward expansion of the annular array.
 20. A method according to claim 16 comprising securing the tubular element and coupling in a forming jig prior to undertaking deformation of the tubular element. 